1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to a routing method in consideration of the power and transmission delay in a wireless ad hoc network and a terminal device adopting the same, and more particularly, to a routing method and a terminal device which can reduce both the power consumption and packet delay by limiting a hop count from a source node to a destination node.
2. Description of the Related Art
A wireless ad hoc network is a temporary network that can be autonomously constructed by a plurality of nodes having mobility. In the wireless ad hoc network serving as a communication network, a plurality of terminal devices, which independently exist in space, perform one-to-one, one-to-many, and many-to-many communications with all appliances existing within radii recognizable to the terminal devices themselves. Recently, the wireless ad hoc network technology has been applied to diverse application fields, such as home networking, sensor networks, and personal area networks, and active research into the wireless ad hoc network has been conducted.
Respective nodes that constitute a wireless ad hoc network have limited transmission ranges. Thus, if a destination, with which a node intends to communicate, is out of the transmission range of the node, then other nodes existing in the transmission range of the node perform packet relay functions to make it possible to perform the data communications with the destination.
FIG. 1 is a view provided to explain a conventional routing method in a wireless ad hoc network.
Referring to FIG. 1, a source node A uses nodes B, C, and D in order to communicate with a destination node E. In this case, the source node A broadcasts a route request (RREQ) that includes information on transmission power in order to set a route between the source node A and the destination node E. The node C receives the RREQ from the source node A, and calculates an accumulative power, which is obtained by accumulating the transmission power required to broadcast the RREQ and the transmission power included in the RREQ received from the source node A.
Then, the node C carries the accumulative power and the transmission power information required to broadcast the RREQ on the RREQ to be broadcast. In this manner, if the RREQ is received in the destination node E, the node E selects the RREQ having the minimum accumulative power included in the received RREQ, and transmits a route reply (RREP) to the node that has transmitted the selected RREQ to set the route.
However, since the conventional routing method in consideration of power in an ad hoc network sets the nodes having the minimum accumulative power as relay nodes, the route length from the source node to the destination node is lengthened as the number of relay nodes is increased. Due to this increase of the route length, packet delay occurs, and this causes the quality of service (QoS) to deteriorate. Accordingly, a routing method in a wireless ad hoc network that supports a proper tradeoff between the power being consumed and the packet delay during the packet transmission is needed.